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NAD+ stands for nicotinamide adenine dinucleotide, the oxidized form of a coenzyme found in all living cells. The molecule consists of two nucleotides, adenine and nicotinamide ribose, joined through phosphate groups. Its chemical formula is C21H27N7O14P2, and the free acid has a molar mass near 663.43 grams per mole. In redox reactions, NAD+ accepts a hydride ion and becomes NADH. The pair NAD+ and NADH participates in hundreds of metabolic reactions, including steps in glycolysis, the citric acid cycle, and oxidative phosphorylation.
In cells, NAD+ functions primarily as an electron carrier. Dehydrogenase enzymes in glycolysis and the citric acid cycle transfer hydride from substrates to NAD+, producing NADH. NADH then delivers electrons to the mitochondrial respiratory chain, supporting ATP synthesis. In fermentation, NADH is reoxidized to NAD+ so that glycolysis can continue. The balance between NAD+ and NADH helps set metabolic flux. Beyond redox, NAD+ serves as a substrate for enzymes that cleave it, including sirtuins, poly(ADP-ribose) polymerases, and CD38. These reactions consume NAD+ and release nicotinamide and ADP-ribose products.
Biosynthesis occurs through salvage, Preiss-Handler, and de novo pathways. In mammals, the salvage pathway from nicotinamide predominates, and NAMPT is often described as rate-limiting. Nicotinamide riboside and nicotinic acid enter related routes that converge on NAD+ production. Tissue NAD+ concentrations vary widely and are maintained by a balance of synthesis and consumption. Some studies report age-related declines in certain tissues, but whether these changes cause disease or can be reversed to improve human health remains an open question.
NAD+ is commonly measured by high-performance liquid chromatography with ultraviolet detection, often at 254 or 260 nm. Enzymatic cycling assays provide higher sensitivity by coupling NAD+ to a reporter reaction. Mass spectrometry can distinguish NAD+ from close analogues and confirm isotope labeling. Sample preparation usually involves rapid quenching of metabolism to prevent interconversion with NADH. Because NAD+ and NADH differ by one hydride, extraction conditions strongly affect the measured ratio.
In aqueous solution, NAD+ is most stable under mildly acidic to neutral conditions and degrades faster at high pH or elevated temperature. The molecule can hydrolyze at the pyrophosphate bond or undergo nonenzymatic cyclization. Buffers, chelating agents, and cold temperatures slow these losses during analysis. Repeated freeze-thaw cycles are generally avoided because they can promote degradation and concentration changes. Light exposure is also controlled, though NAD+ is less photolabile than some related nucleotides.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C21H27N7O14P2 | Oxidized form; NADH adds a hydride equivalent. |
| Molar mass | 663.43 g/mol | Free acid form; salts have different values. |
| CAS Registry Number | 53-84-9 | Common identifier for beta-NAD. |
| Appearance | White to off-white powder | Hygroscopic; may absorb moisture from air. |
| Solubility | Freely soluble in water | Poorly soluble in most organic solvents. |
The molecule was first described in the early twentieth century as a factor that promoted fermentation in yeast extracts. Later work linked it to hydrogen transfer and to the oxidation of nutrients in living tissues. Its structure was resolved as a dinucleotide, which explained why it could accept and donate electrons at specific enzyme sites. Today, NAD+ is recognized as a central substrate and signaling precursor, not merely a metabolic cofactor. Whether all observed NAD+ changes reflect causal signaling remains an open question.
Related compounds include NADH, the reduced form, and NADP+, which carries an additional phosphate group. NADP+ and NADPH often serve in biosynthetic and antioxidant reactions, while NAD+ and NADH are more associated with energy-yielding catabolism. Nicotinamide, nicotinic acid, and nicotinamide riboside are precursors that can enter salvage pathways. The exact contribution of dietary precursors to tissue NAD+ pools is an area of active investigation. Some studies measure labeled precursors to trace those routes.
Nicotinamide adenine dinucleotide, commonly abbreviated NAD+, is a coenzyme present in all living cells. The molecule consists of two nucleotides linked by phosphate groups, with adenine and a nicotinamide ring as its principal features. In its oxidized form, the nicotinamide ring can accept a hydride ion, becoming NADH. This reversible conversion places NAD+ at the center of many electron-transfer reactions. Its role as a redox carrier is well established across bacteria, plants, fungi, and animals.
Beyond redox chemistry, NAD+ acts as a substrate for several enzyme families. ADP-ribosyltransferases, sirtuins, and CD38 ectoenzymes cleave the molecule into nicotinamide and ADP-ribose or related products. These reactions connect NAD+ availability to processes such as DNA repair, chromatin modification, and calcium signaling. Because the coenzyme is used in both electron transfer and signaling, cells maintain separate pools in compartments including the cytosol, mitochondria, and nucleus. The relative sizes and regulation of those pools remain active areas of study.
Cells produce NAD+ through several biosynthetic routes. The salvage pathway recycles nicotinamide, while the Preiss-Handler pathway uses nicotinic acid, and a de novo route can start from tryptophan in some organisms. In mammals, the salvage pathway is generally considered the main source under ordinary conditions. Tissue concentrations vary widely by cell type and compartment, and measured declines with age have been reported in some studies. Whether such changes drive aging or mainly accompany it remains an open question.
In redox reactions, NAD+ accepts a hydride ion, which consists of two electrons and one proton. The hydride adds to the nicotinamide ring at a specific carbon, converting NAD+ into NADH. Dehydrogenase enzymes use this step in glycolysis, the citric acid cycle, and fatty acid oxidation. NADH later donates electrons to the mitochondrial electron transport chain, helping to drive ATP synthesis. The balance between NAD+ and NADH reflects the metabolic state of a cell, and shifts in that balance can alter how pathways operate.
Beyond electron transfer, NAD+ serves as a substrate for enzymes that cleave it and attach its ADP-ribose portion to other molecules. This group includes poly(ADP-ribose) polymerases, CD38, and sirtuins. Such reactions consume NAD+ and can influence its availability for metabolism. Cells replenish NAD+ through a salvage pathway that recycles nicotinamide and through routes starting from tryptophan or vitamin B3 forms. How these synthesis and consumption routes are coordinated across tissues remains an active area of study, and compartment-specific concentrations are difficult to measure directly.
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a dinucleotide built from adenine, nicotinamide, two ribose sugars, and two phosphate groups. The oxidized form carries a positive charge on the nicotinamide ring, while the reduced form, NADH, is neutral. This pair acts as a reversible electron carrier in cells. NAD+ is present in bacteria, plants, animals, and fungi. Its structure allows it to accept and donate electrons without being consumed in the reactions it supports.
=== Gut microbiota === The effect of the low-FODMAP diet on the gut microbiota is not fully understood. It is thought that reduction of fermentable carbohydrates affects the composition and abundance of gut bacteria. FODMAPs are a main food source (prebiotic) for many gut bacteria. Deprived of this food source, there is less bacterial fermentation in the gut and less production of intestinal gas, which may also create conditions which favor certain species of bacteria and disfavor others. There is some evidence for negative effects of the low-FODMAP diet, such as reduction in the numbers of beneficial bacteria (e.g., Bifidobacteria). Such changes are comparable to dysbiosis. Other studies report no significant change in gut microbiota from the low-FODMAP diet. There is also some evidence for positive effects on the gut microbiota, such as improved microbial diversity and increased numbers of potentially beneficial bacterial species. The effect of the low-FODMAP diet on gut microbiota also seems to depend on the medical condition, with more profound changes in microbiota occurring in celiac disease or inflammatory bowel disease, but no significant microbiota changes occurring in IBS. Overall, the low-FODMAP diet may have a positive effect on the gut microbiota compared to normal diets. However, the evidence is mixed and there is significant study heterogeneity, probably because of variation in the methodology and length of the studies, and also differences in the studied populations such as genetics and baseline diet.
=== ICD-11 === Anorexia nervosa is classified under feeding or eating disorders in both the ICD-11 and the DSM-5. Like the DSM-5, the ICD-11 also distinguishes between a binge-purge pattern and a restricting pattern with further subcodes.
==== Withdrawn ==== Kyle Sinclair, former vice chair of the Bexar County Republican Party, candidate for the 28th district in 2024 and nominee for the 20th district in 2022 (remained on ballot, endorsed Teixeira)
Sources: en.wikipedia.org
The formation of an astatine compound with hydrogen—usually referred to as hydrogen astatide—was noted by the pioneers of astatine chemistry. As mentioned, there are grounds for instead referring to this compound as astatine hydride. It is easily oxidized; acidification by dilute nitric acid gives the At0 or At+ forms, and the subsequent addition of silver(I) may only partially, at best, precipitate astatine as silver(I) astatide (AgAt). Iodine, in contrast, is not oxidized, and precipitates readily as silver(I) iodide. Astatine is known to bind to boron, carbon, and nitrogen. Various boron cage compounds have been prepared with At–B bonds, these being more stable than At–C bonds. Astatine can replace a hydrogen atom in benzene to form astatobenzene C6H5At; this may be oxidized to C6H5AtCl2 by chlorine. By treating this compound with an alkaline solution of hypochlorite, C6H5AtO2 can be produced. The dipyridine-astatine(I) cation, [At(C5H5N)2]+, forms ionic compounds with perchlorate (a non-coordinating anion) and with nitrate, [At(C5H5N)2]NO3. This cation exists as a coordination complex in which two dative covalent bonds separately link the astatine(I) centre with each of the pyridine rings via their nitrogen atoms. With oxygen, there is evidence of the species AtO− and AtO+ in aqueous solution, formed by the reaction of astatine with an oxidant such as elemental bromine or (in the last case) by sodium persulfate in a solution of perchloric acid.
== Personal life == Yates lives in Marbella with his wife, Brazilian fitness model Glauce "Gal" Ferreira, whom he had met at the 2008 Arnold Classic. His son with his ex-wife Deb is also a bodybuilder and the two work closely together. Yates practises yoga every day and has described yoga and meditation as life-altering experiences. He has endorsed the use of psychedelics such as ayahuasca for religious and spiritual purposes. He is open about his cannabis use, which predates his bodybuilding career; in a July 2017 appearance on The Joe Rogan Experience, he stated that cannabis has "anti-cancer" properties and said that he is an advocate for its legalisation for this reason in addition to its relaxing properties and temporary increases in respiratory capacity. Yates revealed his belief in Holocaust denial theories whilst being interviewed by Dave Palumbo in April 2018, claiming that the Holocaust death toll had been "exaggerated" and that two forensic studies (which he did not provide the names of) had concluded that no gas was ever used at the Auschwitz concentration camp.
=== End of the Ottoman Empire and leaving Constantinople === Between 1914 and 1918, the First World War caused the collapse of the Ottoman Empire and the ascent to power of the nationalist Mustafa Kemal Atatürk in Turkey. Greece moved to action to overthrow Mustapha Kemal. The Greco-Turkish War broke out in 1919. The massacres of the Greek population living on Turkish soil compelled Raymond, whose Greek-born wife was threatened, to flee his native city for Europe.
The two substrates of this enzyme are 10-hydroxydecanoic acid and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 10-oxodecanoic acid, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 10-hydroxydecanoate:NAD+ 10-oxidoreductase.
Sources: en.wikipedia.org
== Sources == Isotope masses from: National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. Half-life, spin, and isomer data selected from the following sources. National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. IAEA - Nuclear Data Section. Live Chart of Nuclides. Vienna International Centre. Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
==== Reaction with compounds containing active methylene groups ==== In the presence of alkoxides, reactions of ethylene oxide with compounds containing active methylene group leads to the formation of butyrolactones:
There are many mechanisms for the repair of damaged double stranded DNA. PARP1 may function as a synapsis factor in alternative non-homologous end joining. Additionally, it has been proposed that PARP1 is required to slow replication forks following DNA damage and promotes homologous recombination at replication forks that may be dysfunctional. It is possible that PARP1 and PARP3 work together in repair of double-stranded DNA and it has been shown that PARP3 is critical for double-stranded break resolution. There are two hypotheses by which PARP1 and PARP3 coincide. The first hypothesis states that the two (ADP-ribosyl)transferases serve to function for each other's inactivity. If PARP3 is lost, this results in single-strand breaks, and thus the recruitment of PARP1. A second hypothesis suggests that the two enzyme work together; PARP3 catalyzes mono(ADP-ribosyl)ation and short poly(ADP-ribosyl)ation and serves to activate PARP1. The PARPs have many protein targets at the site of DNA damage. KU protein and DNA-PKcs are both double-stranded break repair components with unknown sites of ADP-ribosylation. Histones are another protein target of the PARPs. All core histones and linker histone H1 are ADP-ribosylated following DNA damage. The function of these modifications is still unknown, but it has been proposed that ADP-ribosylation modulates higher-order chromatin structure in efforts to facilitate more accessible sites for repair factors to migrate to the DNA damage.
Sources: en.wikipedia.org
Nicotinamide adenine dinucleotide, with the plus sign indicating the oxidized form. It is a coenzyme present in all living cells. The reduced form is NADH.
No. NAD+ is oxidized and accepts electrons, while NADH is reduced and carries them. Together they form a redox pair central to energy metabolism.
NAD+ itself is not a common dietary component in significant amounts. Precursors such as nicotinamide, nicotinic acid, and nicotinamide riboside can be converted through biosynthetic pathways. Direct absorption of intact NAD+ is limited.
NAD+ and NADH can interconvert quickly after a sample is collected, which can alter the measured ratio. Rapid quenching and cold handling limit enzymatic and chemical changes.